The sensors have been soaked in gasoline, diesel fuel, DOT3 brake fluid, antifreeze, alcohol, motor oil, and colas without detrimental effects on the sensor. Solvents like acetone and methyl ethyl ketone will dissolve some of the inks and destroy the sensor.
The sensor is basically a variable resistor. Typically it only has two leads. In a microprocessor based circuit the sensor is set up in a voltage divider and the change in voltage is read by the processor using an ADC. There are some processors that have an integrated current DAC to bias the sensor with a constant current. The voltage across the sensor is then measured using the microprocessor’s ADC.
FSRs are multiple layers that interact with one another. The resting resistance is generally quite high if not open and when the layers are compressed together the resistance decreases. The Bend Sensor is a single layer construction. It starts at a relatively low resistance when flat and increases as it is bent.
Piezo Sensors typically will give a voltage output when it is bent. Once motionless the sensor gives no feed back until it is moved again. The Bend Sensor will hold its higher resistance value when bent and return to the lower resistance value when returned to its flat state